title: Non-imidazole histamine H3ligands: part V. synthesis and preliminary pharmacological investigation of 1-[2-thiazol-4-yl- and 1-[2-thiazol-5-yl-(2-aminoethyl)]-4-n-propylpiperazine derivatives.
abstract: Series of 1-[2-thiazol-4-yl-(2-aminoethyl)]- and 1-[2-thiazol-5-yl-(2-aminoethyl)]-4-n-propylpiperazine derivatives have been prepared and in vitro tested as H3-receptor antagonists (the electrically evoked contraction of the guinea-pig jejunum). It appeared that by comparison of homologous pairs, the 1-[2-thiazol-5-yl-(2-aminoethyl)]-4-n-propylpiperazines (3a,band4a-d) have much higher potency than their analogous 1-[2-thiazol-4-yl-(2-aminoethyl)]-4-n-propylpiperazines (2a-k). Based on the obtained results, we observed the 5-position of 2-methyl-2-R-aminoethyl substituents in the thiazole ring is favourable for histamine H3receptor antagonist activity, whereas its presence in position 4 leads, almost in each case, to strong decrease of activity.
authors.affiliation: Department of Synthesis and Technology of Drugs, Medical University, Muszyńskiego Street 1, 90-145 Łódź, Poland.
authors.forename: Roman
authors.initials: R
authors.lastname: Guryn
authors.forename: Marek
authors.initials: M
authors.lastname: Staszewski
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Walczyński
keywords: 1-[2-thiazol-4-yl-(2-aminoethyl)]- and 1-[2-thiazol-5-yl-(2-aminoethyl)]-4-n-propylpiperazine derivatives; H3-antagonists; Histamine H3-receptor